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Product category: Industrial Drives/Controls
News Release from: Lenze | Subject: Synchronous AC servo motors and drives
Edited by the Engineeringtalk Editorial Team on 08 December 2005

Lenze drives improve robot performance

Ro-Ber Industrial Robots improves the performance of robots in stacking and palletising applications with Lenze drive technology.

Ro-Ber Industrial Robots of Kamen in Germany, maker of gantry robots used in handling systems worldwide, have improved the performance of its robots in stacking and palletising applications with Lenze drive technology The result was a 30% decrease in the typical cycle times for handling goods

The robots allow coverage of large areas and can pick from overlapping work areas.

Compared with floor mounted robots, gantry designs suit cases where the distances goods need to travel are greater, or the paths are varied.

All moving components are lightened to reduce the inertial loads during acceleration and deceleration.

The modular design lets the robots be adapted for different tasks.

Their ability to achieve positioning dynamically and accurately is a result of the servo drive system.

Lenze synchronous AC servo motors driven by Lenze servo drives achieve a high dynamic response over the whole speed range with delivery of an almost constant torque.

High resolution resolvers built into the motors guarantee positioning and repeatable accuracy.

Load capacities range from 100kg for the FP100 machine to 300kg for the FP300.

The dynamic performance of the servo system achieves short cycle times.

In operation, noise levels are low.

The servo drive system is maintenance free.

The robots are quick to assemble and the programming and commissioning processes are fast due to the independent axes.

Accurate positioning is achieved from the Lenze ETC motion controller.

This combines the advantages of two automation concepts - numerical path control (CNC) and a freely programmable PLC combined into one unit.

The ETC controllers are capable of up to 12 axes and can be panel mounted or built into an industrial PC in card form.

Programming the robots is easier because the standard G-code language is not only suitable for CNC applications but also for all movements in Cartesian space; no special robot language is required.

The ETC motion controller uses two Can interfaces for communication: one for the I/O bus and the other to link to the servo drives.

Here a bank of ECS servo drives obtained their positional information from the drive bus in millisecond clock pulses.

An additional Ethernet TCP/IP communication interface on the ETC controller provides the connection between the drive system and a higher level IPC.

Through this interface the PLC can be programmed, product data transferred and current process parameters diagnosed.

So the customer can programme and gain detailed system diagnostics directly from the PC to the drive, an additional OPC interface enables parameter setting and diagnostics of all nodes connected to the Can interfaces.

With the control software running on a standard industrial PC, all the benefits of PC systems can be exploited: data storage on different media, visualisation, programming and networking of computer systems.

Process and load plan data are stored centrally in a database and the data transferred to the CNC and PLC control units.

The servo system is adapted for multi-axis motions with high overload capacity.

In this application, four axes are controlled by the ECS drives - X, Y, Z (lift axis) and C, which turns the picker arm.

Several of the systems are used side by side for the same area gantry.

The ECS drives are networked with Lenze 8200 vector inverters to control further axis for moving and positioning conveyors and stackers at the operating station.

The ECS multi-axis drive system consists of several axis units powered from a central supply module, saving energy.

The supply module and axis drives are linked with a common DC bus allowing braking energy from individual axes to be fed back and reused by axes that are in acceleration mode.

This reduces the average power requirement and the peak demand.

The common DC bus feature of the ECS drives saves on cabling and external components such as mains fuses and filters.

The ECS servo system is rated for between 2 and 20A per axis with an overload capacity of up to 300%.

Thanks to a winding technique where poles are wound individually prior to assembly, the MCS synchronous motors have a higher than usual copper fill resulting in a high power density.

The resulting strong magnetic flux allows smooth running even at low speeds with cogging torques almost imperceptible.

This aids the positioning resolution of the robot.

The latest magnets are resistant to corrosion and demagnetisation, even at high temperatures.

Large bearings mean that strong high radial forces can be applied to the shaft without adversely affecting life, so the motors can operate with high radial loads.

MCS synchronous motors are available for torques from 0.5 to 190Nm.

On these robots they drive the X, Y and Z axes with a further two motors applied to drive the C axis.

All these synchronous servo motors are fitted with a feedback resolver and permanent magnet brakes for holding and emergency stop.

Lenze also supplied an external brake resistor and system cables of which the motor and resolver cables are suitable for trailing. Request a free brochure from Lenze ...

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